Take a bowl and add in chicken pieces, you can cut both in strips or cubes. It is entirely your choice. Then add black pepper powder, chili sauce, soya sauce, salt and corn flour and mix well. Keep aside for 1 hour or more if you have time. Then heat oil and fry chicken pieces in it. Fry on medium flame and take out of oil when pieces turn crisp and golden in color. Keep aside on a kitchen towel to absorb extra oil. Now in a bowl put in red chili powder remaining soya sauce, chili sauce, black pepper, salt, ketchup and vinegar and mix them all well. Now take a large pan and add in a tablespoon of oil. Allow it to heat up and fry chopped garlic on low flame. After a few seconds, add in all the vegetables cut in one inch cubes, one by one and fry for 5 minutes. Make sure vegetables are little crisp and do not lose their natural color. Then add in fried chicken in the ready mixture and cook for 2 minutes and turn off the flame. Serve hot with boiled or fried rice and enjoy.